Method of improving copper or copper alloys and hardener for use therein



Patented Sept. 30, 1930 UNITED STATES PATENT OFFICE WALTER MACHIN AND WILLIAM BOUCH OBRIEN GOUDIELOCK, OF BARROW-IN-FUR- NESS, ENGLAND, ASSIGNORS TO P-M-G METAL TRUST LIMITED, LONDON, ENG- LAN D METHOD OF IMPROVING COPPER OR COPPER ALLOYS AND HARDENER FOR USE 'IHEREIN No Drawing. Application filed J'u1y 10, 1929, Serial No. 377,338, and in Great Britain April i, 1929.

This invention relates to the manufacture of copper alloys and has for its object to provide an improved method of manufacture whereby alloys are produced of the character of bronzes or brasses for example but having improved properties and capable of use in conditions which will not normally admit of the employment of the copper alloys referred to and cast iron, and the steel employed in making the mixture may include one or more of the metals, nickel, chromium, molybdenum, tungsten or vanadium. The phosphorus acts as a deoXidiZer, and also confers better metallurgical properties on the final alloy. Some manganese may also be added if desired.

Some copper alloys containing iron and silicon have previously been made, and for this purpose iron or steel containing only small amounts of carbon and ferro-silicon have been used; the melting points of these substances are much higher than that of copper and overheating of the alloys is therefore diflicult to avoid, and porous alloys are liable to be produced with irregular casting properties and non-uniform mechanical values. Pro-alloys made according to the present invention have lower melting points than those of iron or steel or ferro-silicon and when they are alloyed with copper or copper alloys overheating is avoided and the alloys show very regular casting properties and uniform good mechanical values.

In carrying the invention into effect according tothe preferred form the hardener or pre-alloy is prepared as a separate alloy by hrst preparing the iron constituent which consists preferably of castiron, or of semi-steel the required amount of silicon has been incorporated into the melt. To this melt ferromanganese may be added, the whole molten mass so prepared being then mixed with the requisitequantity of copper. Subsequently the entire homogeneous molten mixture containing all the desired ingredients is heated to the required extent to bring it to a Suficiently liquid condition or without further heating if it is already sufficiently liquid it is finally cast.

The composition of this hardener alloy varies in accordance with the particular charactcristics which it is desired to give to the filial copper content alloy but usually the hardener is made With the proportions of its constituents maintained Within about the following limits:

Iron 5 to 30 per cent S1l1con 10 to 70 per cent Copper not less than 20 per cent Phosphorus and manganese may be added if desired in amounts not exceeding 10% phosphorus and 15% manganese.

The hardener above described can be applied, for example, to the production of a copper alloy which will fulfill the functions of gun-metal but at the same time possess increased mechanical properties. In applying the hardener or pre-alloy for this purpose the tin content of a normal gun metal of the approximate constitution 88% copper, 10% tin, and 2% zinc would be replaced by a proportion of a hardener or pre-alloy manufactured as above described and for this particular purpose the hardener or pre-alloy hasbeen employed with its constituents in the follow ing proportions Percent Iron 16 Silicon 7 40 zinc but if esired, the zinc or a large part thereof may also be included in the hardener and any further quantity of zinc which may be required to give to the final alloy obtained the recise composition desired may be added to the melted copper. The hardener may be used to re'slgce the tin content wholly or in part accor to the requirements to be met y the finishe alloy. The hardener may also be .used in varying proportions v to replace wholly or in part the content of zinc or other metals in brasses or s ecial brasses.

For example an a oy prepared from 88% copper 10%. of the har ener and 2% zinc V was found to possess excellent casting properties and sand-cast bars gave on test the following mechanical properties i (a) A yield point of approximately 12 tons r square inch.

(b) An ultimate tensile strength of approximately 22 tons per square inch..

(0) An elongation of approximately 12 r cent on 2 inches.

(d) A Brinell hardness of approximately 110, with: a 10 millimetre ball and a load of 2,000 kilogrammes.

It has also been found that the alloy can be extruded; one sample of extruded bar was found to have the following properties Yield point; 28 tons/sq. inch Ultimate tensile strength 40.4: tons/sq. inch Elongation on 2 inches 22 per cent The alloy can be forged hot, by which ro'oess the mechanical properties are modied and improved. The following are typical examples of'tests on such forged alloy (1') Hot forged: Finished at a 'red heat Yield point 18 tons/sq. inch Ultimate stress 32.2 tons/sq. inch Elongation on 2 inches 52 percent I i (ii) H at forged: Finished at a black heat Yield point 36.8 tons/sq. inch Ultimate stress 4.2 tons/sq. inch Elongation on 2 inches- 17 per cent that usually employed in the It has been found that the properties oft-hese alloys may be modified by heat treatment, consisting in heating them to temper- 7 atures between 800 C. and the temperature 31 at which they beginto melt; followed by cooling rapidly as by immersing in water or oil. Cast bars of the gun metal substitute alloy,

6 for example, were found to have a tensile strength of tons per square inch and an elongation of 28 per cent after heating at 900 C. for one hour and quenching in water.

The heat treatment may also consist in quenching as described from temperatures between 800 C. and the melting temperature followed by reheating to temperatures not exceeding 450 C.

It has also been found that this alloy possesses excellent properties at high temperatures. In one series of tests, the following results were obtained Tensile Tempera- 33 strength tures C. (tons sq.ln.)

We claim alloying silicon, iron and copper'to consti-" tute a hardener or pre-alloy in the proportions of 5 to iron, 10 to 7 0% silicon and not less than 20% copper; and thereupon melting said pre-alloy with a copper alloy.

3. The method of manufacturing copper alloys containing silicon and iron by first alloying silicon, iron, copper and phosphorus to constitute a hardener or pre-alloy in the proportions of 5 to 30% iron, 10 to silicon and not less than 20% copper and phosphorus not more than 10%; and thereupon melting said pre-alloy with copper.

4. The method of manufacturing copper alloys containing silicon and iron by first alloying silicon, iron, copper and phosphorus to constitute a hardener or pre-alloy in the proportions of 5 to 30% iron, 10 to 70% silicon and not less than 20% copper and phosphorus not more than 10%; and there- 7 upon meltingsaid pre-alloy with a copper allo 5. A hardener or pro-alloy for use in the manufacture of alloys consisting predominantly of copper; said pro-alloy containing 5 to 30% iron; 10 to 70% silicon; and. not less than 20% copper.

6. A hardener or pro-alloy for use in the manufacture of alloys consisting predominantly of copper; said pro-alloy containing 5 to 30% iron; 10 to 70% silicon; not less than 20% copper and not more than 10% of phosphorus.

In testimony whereof we have hereunto set our hands.

WALTER MACHIN. WILLIAM BOUCH O'BRIEN GOUDIELOCK. 

